Claims
- 1. A photochromic polyurethane film comprising:
a polyurethane film having a thickness in the range of about 10 μm to 250 μm; at least one organic photochromic compound; a stabilizer system having two hindered amine light stabilizers and one phenolic antioxidant; said photochromic compound having a concentration of approximately 0.1 % to 6% by weight; said stabilizer system having a concentration of approximately 1 % to 9% by weight; said stabilizer system having a formulation to provide at least a 40% of improvement in the light fatigue resistance of the photochromic polyurethane film over a film not having said formulation; and said stabilizer system having a formulation to provide a change of less than 6 units in b* of CIELAB at the clear state for said photochromic polyurethane film.
- 2. A photochromic polyurethane film of claim 1 wherein said stabilizer system comprises:
(a) 60% to 90%, by weight, two hindered amine light stabilizers being selected from the group consisting of bis(1,2,2,6,6-pentamethyl-4-piperidinyl)-[[3,5-bis(1,1-dimethylethyl)]-[4-hydroxyphenyl]methyl]butyl malonate; Bis(1,2,2,6,6-pentamethyl-4-piperidinyl)sebacate; methyl(1,2,2,6,6-pentamethyl-4-piperidinyl)sebacate; bis(2,2,6,6-tetramethyl4-piperdinyl)decanedioate; 1-acetyl4-(3-dodecyl-2,5-dioxo-1-pyrrolidinyl)-2,2,6,6-tetramethyl-piperi dine and N-unsubstituted HALS compounds, N-methylated HALS compounds. (b) 10% to 40%, by weight, one phenolic antioxidant being selected from the group consisting of tetrakis-(methylene-3-(3′′,5′′-di-t-butyl-4′-hydroxyphenyl)propionate]methane; 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4′-hydroxybenzyl)benzene; 1,3,5-tris(3,5-di-tert-butyl-4′-hydroxybenzyl)isocyanurate; 3,5-di-tert-butyl-4-hydroxyhydrocinnamic triester with 1,3,5-tris(2-hydroxyethyl)s-triazine-2,4,6-(1 H,3H,5H)-trione; 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)s-triazine-2,4,6-(1H, 3H,5H)-trione;
- 3. A photochromic polyurethane film of claim 2 wherein said two hindered amine light stabilizers are bis(1,2,2,6,6-pentamethyl-4-piperidinyl)-[[3,5-bis(1,1-dimethylethyl)]-[4-hydroxyphenyl]methyl]butyl malonate and Bis(1,2,2,6,6-pentamethyl-4-piperidinyl)sebacate-methyl(1,2,2,6,6-pentamethyl-4-piperidinyl)sebacate, and said phenolic antioxidant is tetrakis-(methylene-3-(3′,5′-di-t-butyl-4′-hydroxyphenyl)propionate]methane.
- 4. A photochromic polyurethane film of claim 1 wherein said photochromic compound is a photochromic naphthopyran.
- 5. A photochromic polyurethane film of claim 1 wherein said polyurethane is an aliphatic polyurethane.
- 6. A photochromic polyurethane film of claim 1 wherein said polyurethane is an aliphatic polyester polyurethane.
- 7. A photochromic polyurethane film of claim 1 wherein the film is laminated.
- 8. A photochromic polyurethane film of claim 7 wherein the laminate is incorporated into an eyewear lens.
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of priority from U.S. Provisional Application Serial No. 60/442,425 filed on Jan. 24, 2003, the contents of which are hereby incorporated by reference.
Provisional Applications (1)
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Number |
Date |
Country |
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60442425 |
Jan 2003 |
US |